Personality can be defined in terms of enduring individual differences in emotional, interpersonal, experiential, and motivational styles. The five factors of Neuroticism, Extraversion, Openness to Experience, Agreeableness, and Conscientiousness provide a comprehensive taxonomy of personality traits for the description of personality in aging men and women. In an effort to improve personality assessments, couples were interviewed to determine reasons for their disagreements in describing each other. Idiosyncratic understanding of words, use of different frames of references, and the inaccessibility of covert thoughts and feelings were among the most common reasons. Findings suggest that multiple sources of personality information should be used whenever feasible.